1 Introduction The weathered crust rare earth deposits is one of the most significant rare earth deposits,which are mostly distributed in southern China,especially in the south of Jiangxi province(Chi et al.,2007).The...1 Introduction The weathered crust rare earth deposits is one of the most significant rare earth deposits,which are mostly distributed in southern China,especially in the south of Jiangxi province(Chi et al.,2007).The compositions of these deposits,which are weathered from igneous rocks such as granite through biological,physical or chemical展开更多
The hydrogen adsorption on the one and three Ni-decorated LiB （001） 2 × 2 surface is investigated by the first principles study. It is demonstrated that Ni atoms are preferentially adsorbed on the top B atom, a...The hydrogen adsorption on the one and three Ni-decorated LiB （001） 2 × 2 surface is investigated by the first principles study. It is demonstrated that Ni atoms are preferentially adsorbed on the top B atom, and form a covalent bond of NiB and an ionic bond of NiLi on the surface. Four H2 molecules can adsorb on the one- Ni-decorated LiB （001） surface, and the average adsorption energy is in a range from -0.35 to -0.58eV/H2. The charge population analysis shows that the dipole moments on the Ni decorated surface is responsible for the polarization and adsorption of H2. Then, we show that three Ni atoms can be decorated on the LiB （001） 2 × 2 surface, and form a Ni3B nano cluster on the surface, which agrees with experimental results. Three Ni- decorated LiB （001） can adsorb up to six H2 molecules, indicating that the Ni-decorated LiB （001） system might be a promising hydrogen storage material.展开更多
Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 time...Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 times and ～1.3 times higher than that of the pristine Li4SiO4 at 500 and 600℃, respectively. The kinetic study further indicated that the reaction rates of the lithium diffusion process is greatly improved by K and AI doping, and the lithium diffusion rate of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2 times higher than that of the pristine Li4SiO4 at 575-650 ℃. K and AI doping increases the adsorption capacity of Li4SiO4-based adsorbents, and widens its effective adsorption temperature range展开更多
Adsorptive enhancements of several water-soluble polymers on copper(Ⅱ) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode. Increases in peak current of cu(Ⅱ) were observed in al...Adsorptive enhancements of several water-soluble polymers on copper(Ⅱ) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode. Increases in peak current of cu(Ⅱ) were observed in alkaline carbonate media. The enhancing power of poly(vinyl alcohol), starch and polyallylamine is 15, 4. 1, and 2.5 times, repectively展开更多
Adsorptive enhancements of several inorganic salts on copper(II) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode Increase in peak curren of cu(II) were observed in alkaline phosp...Adsorptive enhancements of several inorganic salts on copper(II) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode Increase in peak curren of cu(II) were observed in alkaline phosphate or media owing to adsorption Silicate can also enhance the peak current of Cu(II). The enhancing power phosphate,carbonate, and silicate is 33, 26, and 8.9 times, respectively.展开更多
In the 0.3mol/L NH_4Cl supporting electrolyte,salicyl-fluorone exhibits a sensitive adsorptive wave by using linear scanning voltammetry with Ep_1=-0.70V and a diffusion wave with Ep_2=-0.68V(v8,SCE)at pH 2.5.On the s...In the 0.3mol/L NH_4Cl supporting electrolyte,salicyl-fluorone exhibits a sensitive adsorptive wave by using linear scanning voltammetry with Ep_1=-0.70V and a diffusion wave with Ep_2=-0.68V(v8,SCE)at pH 2.5.On the surface of HMDE, the adsorption of salieyl-fluorone obeys Frumkin adsorption isotherm.The adsorption coefficient(B),and attractive factor(v)and the amount of saturated adsorption(Γs)have been determined.展开更多
Kinetics of oxygen adsorption on single crystal Mn<sub>5</sub>Si<sub>3</sub> （111） surface and initial surface oxidation were investigated. Oxygen chemisorbs dissociatively at room temperatur...Kinetics of oxygen adsorption on single crystal Mn<sub>5</sub>Si<sub>3</sub> （111） surface and initial surface oxidation were investigated. Oxygen chemisorbs dissociatively at room temperature on Mn and Si atoms. A fast oxidation of Si atoms occurs followed by oxidation of Mn atoms at RT. The MnO<sub>2</sub> was reduced by Si atoms and the SiO was oxidized further to SiO<sub>2</sub> during the sample heating.展开更多
Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic（Methylene Blue,MB） and anionic dyes（Congo Red,CR） from synthetic wastewater.Nanocomposite was characterized by TEM...Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic（Methylene Blue,MB） and anionic dyes（Congo Red,CR） from synthetic wastewater.Nanocomposite was characterized by TEM,SEM,FT-IR,EDS analysis and zeta potential.TEM analysis indicated that the particle diameter of nanocomposite was in the range of 14 to23 nm.Various important parameters viz.contact time,concentration of dyes,nanocomposite dosage,temperature and solution pH were optimized to achieve maximum adsorption capacity.In the case of MB,removal decreased from 99.82%to 93.67%while for CR,removal decreased from 88.55%to 75.69%on increasing dye concentration from 100 to 450 mg/L.pH study confirmed the higher removal of CR in acidic range while MB removal was higher in alkaline range.Kinetic study revealed the applicability of pseudo-second-order model for the adsorption of both dyes.Negative values of AG0 for both systems suggested the feasibility of dye removal and support for spontaneous adsorption of CR and MB on nanocomposite.Nanocomposite showed 277.77 and 238.09 mg/g Langmuir adsorption capacity for MB and CR respectively.Desorption of dyes from the dye loaded nanocomposite was easily carried out with acetone.The results indicate that the prepared malachite@clay nanocomposite is an efficient adsorbent with high adsorption capacity for the aforementioned dyes.展开更多
The adsorption of hydrogen on zinc oxide has been a very interesting topic. A. L.Dent and R. J. Kokes studied the kinetics and mechanism by IR, H<sub>2</sub>-D<sub>2</sub> exchange and BETmeasu...The adsorption of hydrogen on zinc oxide has been a very interesting topic. A. L.Dent and R. J. Kokes studied the kinetics and mechanism by IR, H<sub>2</sub>-D<sub>2</sub> exchange and BETmeasurements. They found that there are two types of hydrogen adsorption, in whichtype Ⅰ is rapid and reversible whilst trpe Ⅱ is slow and irreversible. B. Fubini et al.展开更多
Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater s...Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater samples are of major concern from an environmental point of view.In the present work,an effective spectrophotometric method has been reported using 5,7-dibromo-8-hydroxyquinoline(DBHQ)as a complexing agent for Cd^(2+).This method has advantages like using recyclable,less toxic solvents and easy sample preparation.The limit of detection,limit of quantification,and sensitivity of the proposed method were found to be 33.30,36.70 mg L^(−1),and 2×10^(−3),respectively.The DBHQ method was validated using atomic absorption spectroscopy,and the recovery percentage was more than 98%.These results indicate that DBHQ can be effectively used for monitoring Cd^(2+)in aqueous systems.The method developed was further employed for monitoring Cd^(2+)adsorption on calcium alginate(AL)hydrogels.Batch adsorption studies were done to optimize parameters of Cd^(2+)removal using AL hydrogels,and the data obtained were used for kinetic and thermodynamic studies.Kinetic studies indicated that the pseudo-first-order model showed better fitting,and thermodynamic studies showed Freundlich-like adsorption.The maximum adsorption capacity of Cd^(2+)on AL hydrogels was found to be 56.45 mg g^(−1).The validation studies of DBHQ were performed using statistical analysis methods like t-tests and one-way variance.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 41302030)Fundamental Research Project of Chinese Academy of Geological Sciences (Grant No. YYWF201619)+1 种基金National Key R&D Program of China (Grant No.2016YFC0600605)China Geological Survey Program (DD20179152)
文摘1 Introduction The weathered crust rare earth deposits is one of the most significant rare earth deposits,which are mostly distributed in southern China,especially in the south of Jiangxi province(Chi et al.,2007).The compositions of these deposits,which are weathered from igneous rocks such as granite through biological,physical or chemical
基金Supported by the National Natural Science Foundation of China under Grant No 60976069the Science Innovation Training Program under Grant No 2014107191081the Science Foundation of Yan’an University under Grant No YD2014-02
文摘The hydrogen adsorption on the one and three Ni-decorated LiB （001） 2 × 2 surface is investigated by the first principles study. It is demonstrated that Ni atoms are preferentially adsorbed on the top B atom, and form a covalent bond of NiB and an ionic bond of NiLi on the surface. Four H2 molecules can adsorb on the one- Ni-decorated LiB （001） surface, and the average adsorption energy is in a range from -0.35 to -0.58eV/H2. The charge population analysis shows that the dipole moments on the Ni decorated surface is responsible for the polarization and adsorption of H2. Then, we show that three Ni atoms can be decorated on the LiB （001） 2 × 2 surface, and form a Ni3B nano cluster on the surface, which agrees with experimental results. Three Ni- decorated LiB （001） can adsorb up to six H2 molecules, indicating that the Ni-decorated LiB （001） system might be a promising hydrogen storage material.
基金supported by the National Natural Science Foundation of China(Nos. 21476160, 21476159]the Natural Science Foundation of Tianjin(Nos.15JCYBJC23000,15JCZDJC37400)
文摘Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 times and ～1.3 times higher than that of the pristine Li4SiO4 at 500 and 600℃, respectively. The kinetic study further indicated that the reaction rates of the lithium diffusion process is greatly improved by K and AI doping, and the lithium diffusion rate of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2 times higher than that of the pristine Li4SiO4 at 575-650 ℃. K and AI doping increases the adsorption capacity of Li4SiO4-based adsorbents, and widens its effective adsorption temperature range
文摘Adsorptive enhancements of several water-soluble polymers on copper(Ⅱ) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode. Increases in peak current of cu(Ⅱ) were observed in alkaline carbonate media. The enhancing power of poly(vinyl alcohol), starch and polyallylamine is 15, 4. 1, and 2.5 times, repectively
文摘Adsorptive enhancements of several inorganic salts on copper(II) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode Increase in peak curren of cu(II) were observed in alkaline phosphate or media owing to adsorption Silicate can also enhance the peak current of Cu(II). The enhancing power phosphate,carbonate, and silicate is 33, 26, and 8.9 times, respectively.
文摘In the 0.3mol/L NH_4Cl supporting electrolyte,salicyl-fluorone exhibits a sensitive adsorptive wave by using linear scanning voltammetry with Ep_1=-0.70V and a diffusion wave with Ep_2=-0.68V(v8,SCE)at pH 2.5.On the surface of HMDE, the adsorption of salieyl-fluorone obeys Frumkin adsorption isotherm.The adsorption coefficient(B),and attractive factor(v)and the amount of saturated adsorption(Γs)have been determined.
文摘Kinetics of oxygen adsorption on single crystal Mn<sub>5</sub>Si<sub>3</sub> （111） surface and initial surface oxidation were investigated. Oxygen chemisorbs dissociatively at room temperature on Mn and Si atoms. A fast oxidation of Si atoms occurs followed by oxidation of Mn atoms at RT. The MnO<sub>2</sub> was reduced by Si atoms and the SiO was oxidized further to SiO<sub>2</sub> during the sample heating.
基金financial supports from the Regional Council of South-Savo and the City of Mikkeli,Finland
文摘Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic（Methylene Blue,MB） and anionic dyes（Congo Red,CR） from synthetic wastewater.Nanocomposite was characterized by TEM,SEM,FT-IR,EDS analysis and zeta potential.TEM analysis indicated that the particle diameter of nanocomposite was in the range of 14 to23 nm.Various important parameters viz.contact time,concentration of dyes,nanocomposite dosage,temperature and solution pH were optimized to achieve maximum adsorption capacity.In the case of MB,removal decreased from 99.82%to 93.67%while for CR,removal decreased from 88.55%to 75.69%on increasing dye concentration from 100 to 450 mg/L.pH study confirmed the higher removal of CR in acidic range while MB removal was higher in alkaline range.Kinetic study revealed the applicability of pseudo-second-order model for the adsorption of both dyes.Negative values of AG0 for both systems suggested the feasibility of dye removal and support for spontaneous adsorption of CR and MB on nanocomposite.Nanocomposite showed 277.77 and 238.09 mg/g Langmuir adsorption capacity for MB and CR respectively.Desorption of dyes from the dye loaded nanocomposite was easily carried out with acetone.The results indicate that the prepared malachite@clay nanocomposite is an efficient adsorbent with high adsorption capacity for the aforementioned dyes.
文摘The adsorption of hydrogen on zinc oxide has been a very interesting topic. A. L.Dent and R. J. Kokes studied the kinetics and mechanism by IR, H<sub>2</sub>-D<sub>2</sub> exchange and BETmeasurements. They found that there are two types of hydrogen adsorption, in whichtype Ⅰ is rapid and reversible whilst trpe Ⅱ is slow and irreversible. B. Fubini et al.
文摘Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater samples are of major concern from an environmental point of view.In the present work,an effective spectrophotometric method has been reported using 5,7-dibromo-8-hydroxyquinoline(DBHQ)as a complexing agent for Cd^(2+).This method has advantages like using recyclable,less toxic solvents and easy sample preparation.The limit of detection,limit of quantification,and sensitivity of the proposed method were found to be 33.30,36.70 mg L^(−1),and 2×10^(−3),respectively.The DBHQ method was validated using atomic absorption spectroscopy,and the recovery percentage was more than 98%.These results indicate that DBHQ can be effectively used for monitoring Cd^(2+)in aqueous systems.The method developed was further employed for monitoring Cd^(2+)adsorption on calcium alginate(AL)hydrogels.Batch adsorption studies were done to optimize parameters of Cd^(2+)removal using AL hydrogels,and the data obtained were used for kinetic and thermodynamic studies.Kinetic studies indicated that the pseudo-first-order model showed better fitting,and thermodynamic studies showed Freundlich-like adsorption.The maximum adsorption capacity of Cd^(2+)on AL hydrogels was found to be 56.45 mg g^(−1).The validation studies of DBHQ were performed using statistical analysis methods like t-tests and one-way variance.
